In recent years, there has been proposed a technology for performing priming, blood-return and substitution (emergent substitution) using dialysate to be supplied to a dialyzer or a technology for using the dialysate as substitution fluid for dialysis treatment (especially on-line HDF treatment or on-line HF treatment) in a dialysis apparatus as a blood purification apparatus. In Patent Document 1 below, there is disclosed a dialysis apparatus comprising a substitution line of which one end being connected to a dialysate extraction port (collection port) arranged at a predetermined position of a dialysate introduction line and the other end being connected to a blood circuit (arterial blood circuit and venous blood circuit), and a substitution pump arranged on the substitution line. In such a dialysis apparatus, the dialysate in the dialysate introduction line can be supplied to the blood circuit (arterial blood circuit and venous blood circuit) by driving the substitution pump.
In usual, a cap (open/close member) are detachably mounted on the dialysate extraction port, and thus the substitution line can be connected to the dialysate extraction port when the cap is removed and leakage of the dialysate flowing through the dialysate introduction line can be prevented by mounting the cap on the dialysate extraction port when the substitution line is not connected thereto. For example, when performing cleaning or disinfection of pipes such as the dialysate introduction line and dialysate discharging line through which dialysate flows, leakage of flushing water or disinfection liquid can be prevented by flowing flushing water or disinfection liquid through pipes with keeping the cap mounted on the collection port.
On the other hand, a connection member is mounted on a tip end of a connection line such as the substitution line adapted to be connected to the collection port to extract dialysate flowing through the dialysate introduction line by connecting the connection member to the collection port and then to supply the extracted dialysate to a desired portion (e.g. blood circuit etc.) via the connection line. In addition, it is possible to extract a predetermined amount of dialysate flowing through the dialysate introduction line by connecting the tip end of the connection member comprising a syringe etc.